Ways to disconnect drivechain from motor

Discussion in 'Motorized Bicycle General Discussion' started by Jimmytonga, Feb 6, 2013.

  1. Jimmytonga

    Jimmytonga New Member

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    Hey all,
    I recently got a 66cc motor up and running on a mountain bike frame. I love it, but there is one thing that I wish I could change: I hate the fact that my whole drivechain rotates no matter what. I am trying to find a way to disconnect the chain so that during long downhills when i turn off the motor, the chain stops spinning too.
    So far the only thing i found to do this is the SBP shift kit. Is there any other mod that can do this?
    Thanks
     
  2. The_Aleman

    The_Aleman New Member

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    <removed out of protest to certain "staff" practices in this forum.>
     
    #2 The_Aleman, Feb 6, 2013
    Last edited: Mar 14, 2015
  3. MotorBicycleRacing

    MotorBicycleRacing Active Member

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    This HybriPed (Hybrid Pedal) Sprocket would do want you want but it has been out of stock for quite a while.

    http://www.bicycle-engines.com/HybriPed-Hybrid-Pedal-Sprocket.html
     
  4. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    An angle grinder works pretty well, as does a chain breaker :D
     
  5. 2door

    2door Moderator
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    I believe what the OP is asking for is a way to disengage the chain while riding. Removing the chain or sprockets that require him to stop and remove pins isn't what he wants.

    I'm not really sure what the issue is except for chain noise. He wants to disengage while riding down hills. Just pull the clutch lever in, kill the engine and coast. I do it all the time. Yep, there's a little chain noise but not enough to be a concern, at least to me.

    Tom
     
  6. nightcruiser

    nightcruiser New Member

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    When I was running the kit chain with the chain tensioner the noise and drag from the drive chain was unbearable, I too found myself wishing I had some way to disengage the motor chain from the rear wheel. After I switched over to #41 chain and started running without the chain tensioner the noise and resistance from the motor chain went WAY down and it's no longer an issue for me....
     
  7. Groove

    Groove New Member

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    I agree with the OP, in that it would be nice to be able to disengage the drive chain and coast down a hill without that 415 chain whippin' around so angrily (word?). It hasn't been a problem for me, but I'd have some peace of mind knowing the chain couldn't suddenly break and snap me in the acorns. (Could that happen?)
     
  8. jji7skyline

    jji7skyline New Member

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    You could get a jackshaft kit.
     
  9. Jimmytonga

    Jimmytonga New Member

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    Thanks for all the replys.
    The reason I dont like the drivechain spinning is because of all the resistance from the chain and bearing. Also like @Groove said, it feels really sketchy.

    @jji7skyline: What is the jackshaft kit exactly? Is it pretty much like the shift kit?
    @motorbicycleracing: The Hybriped looks great, except that ideally i would be able to disengage it while riding.
    @The Aleman: That might be exactly what I want. So for that mod you would need a pull start kit, right? Also have you ever done this? If so you should post some pics!

    Thanks
     
    #9 Jimmytonga, Feb 6, 2013
    Last edited: Feb 6, 2013
  10. NunyaBidness

    NunyaBidness Active Member

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    Hey Jimmy, welcome to the best motorbike forum on the net.
    The shift kit is a jackshaft kit. Not all jackshaft kits are shift kit tho.
    Hope that helps at least a little.
     
  11. Jimmytonga

    Jimmytonga New Member

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    Is there any jackshaft kits on the market besides the SBP one and the BikeBerry one? Like ones that are nicer to my bank account?

    Thanks
     
  12. jji7skyline

    jji7skyline New Member

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    I'm getting one from eBay for $160 on my next build, since SBP don't ship to Australia I don't think.

    You should check eBay as well.
     
  13. The_Aleman

    The_Aleman New Member

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    <removed out of protest to certain "staff" practices in this forum.>
     
    #13 The_Aleman, Feb 8, 2013
    Last edited: Mar 14, 2015
  14. Groove

    Groove New Member

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    Update:

    Well, I finally built up the courage to take Nightcruiser's suggestion about removing the chain tensioner. (Spool fell off during a ride and of course it rolled directly into the sewer grate as I was running after it for about 50 yards). So I walked the bike back to my garage, removed the tensioner bracket and a few chain links..

    It works way better than I would have imagined. Much less rolling resistance and MUCH quieter. The difference is night and day for me. The funny thing is, this is my first build that still has the rag joint...
     
  15. MotorBicycleRacing

    MotorBicycleRacing Active Member

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    Sick Bike Parts ships a lot of their shift kits and parts to Australia.
     
  16. nightcruiser

    nightcruiser New Member

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    Welcome to the other side! LOL

    I had the same exact experience, beside being problematic and always needing to be checked every ride and tweaked often, the tensioner made a lot of noise and caused a lot of drag when I pedaled. Once it was removed my bike rode more like, well, a bike! LOL I was apprehensive at first like you about removing the tensioner entirely, but once I did the improvement was so great, my bike is pushing near 2,000 miles with absolutely zero chain issues. (running #41 industrial/farm chain) When I first built the bike and was running with the tensioner I was constantly checking the chain, checking the tensioner, before a ride, during rides, after rides... After I removed the tensioner I kept my eye on it for a few hundred miles, out of habit I guess, eventually I got used to the idea that I didn't have to fiddle with the chain every ride......

    BTW I'm still running the rag joint too, cause my sprocket is dead center with absolutely no wobble. Rag joints can be a PITA to get setup right with no wobble, but if you can manage to get one balanced out well they work just fine. It's the wobbling and vibrations that cause a lot of the problems with these little HT kits, if you take your time and smooth them out your bike will ride smoother and last longer....
     

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